Calculus is the branch of mathematics studying the rate of change of quantities (which can be interpreted as slopes of curves) and the length, area, and volume of objects. The chain rule is a formula for the derivative of the composition of two functions in terms of their derivatives.
If the larger angle is x and the smaller angle is y, y=(1/2)x+30 since it's 30 more than 1/2 of it. In addition, x+y=180 since they are supplementary. Plugging y=(1/2)x+30 into that, we get x+x/2+30=180=1.5x+30. Subtracting 30 from both sides, we get 1.5x=150. Next, we can divide both sides by 1.5 to get x=100 and y=(1/2)*100+30=50+30=80
